Step 1

Preparation Put oven rack in lower third of oven and preheat oven to 450°F.

Step 2

Put beef, fat side up, in a small roasting pan and sprinkle all over with salt and pepper. Stir together flour and dry mustard, then pat onto top and sides of roast to form a thick coating.

Step 3

Roast beef 20 minutes. Reduce oven temperature to 350°F and roast until thermometer inserted into center of meat registers 115°F, about 1 1/4 hours more. Transfer beef to a cutting board and let stand, uncovered, 25 minutes. Meat will eventually reach 125°F (medium-rare).